Hammer Shark is significantly better than this card because of its ability to swarm the board with Yomi Ships, Needle Sunfish, Lost Blue Breaker, Star Boy, and Beautunaful Princess (with an ideal hand you can get 3 beaters on the board turn 1). Hammer Shark has an entire Tier 1 deck built around it and Uminotaurus is just a mediocre beater with a ok at best effect